Motor-driven steering assist apparatus

Abstract

A motor-driven steering assist apparatus is structured such that a single unit body covered by housings has an input shaft, an output shaft, a torque sensor, an electric motor and a gear train built-in, and elastic members are interposed between an attaching portion provided in the housing and a vehicle body side attaching stay.

1. A motor-driven steering assist apparatus interposed between a steering wheel and a wheel side steering member, and assisting a steering force which a driver applies to the steering wheel on the basis of a generating torque of an electric motor, comprising:
 a single unit body covered by a housing having an input shaft to which the steering wheel is connected, an output shaft to which the wheel side steering member is connected, a torque sensor which is provided between the input shaft and the output shaft, an electric motor which is driven in correspondence to a detected torque of the torque sensor, and a gear train which transmits a rotation of the electric motor to the output shaft built-in, an elastic member is interposed between an attaching portion provided in the housing and a vehicle body side attaching stay, wherein the elastic member is provided in both sides of the attaching portion provided in the housing, and the attaching portion provided in the housing is pinched between forked support portions of the vehicle body side attaching stay via the elastic member. 
 
   
   
     2. A motor-driven steering assist apparatus as claimed in  claim 1 , wherein the housing is constituted by first to third housings,
 the first housing supports an upper end portion of the input shaft and the torque sensor, 
 the second housing supports an upper end portion of the output shaft, the electric motor and the gear train, 
 the third housing supports a lower end portion of the output shaft, and 
 the attaching portion is provided in an outer periphery of the second housing. 
 
   
   
     3. A motor-driven steering assist apparatus as claimed in  claim 2 , wherein the attaching portion comprises attaching bosses provided at a plurality of positions in a circumferential direction of an outer periphery of the second housing. 
   
   
     4. A motor-driven steering assist apparatus as claimed in of  claim 2 , wherein the motor-driven steering assist apparatus is applied to a snowmobile. 
   
   
     5. A motor-driven steering assist apparatus as claimed in of  claim 2 , wherein the motor-driven steering assist apparatus is applied to a snowmobile. 
   
   
     6. A motor-driven steering assist apparatus as claimed in  claim 1 , wherein the attaching portion has an annular concave portion, and the elastic member is provided with an annular convex portion in one surface side,
 the forked support portion is provided with upper and lower support pieces, and 
 wherein in a state in which the elastic member is attached to the forked support portion, the annular convex portion provided in one surface side of the elastic member pinched between the upper and lower support pieces of the forked support portion is fitted to the annular concave portion by being compression deformed with no gap. 
 
   
   
     7. A motor-driven steering assist apparatus as claimed in of  claim 1 , wherein the motor-driven steering assist apparatus is applied to a snowmobile. 
   
   
     8. A motor-driven steering assist apparatus as claimed in of  claim 1 , wherein the motor-driven steering assist apparatus is applied to a snowmobile. 
   
   
     9. A motor-driven steering assist apparatus interposed between a steering wheel and a wheel side steering member, and assisting a steering force which a driver applies to the steering wheel on the basis of a generating torque of an electric motor, comprising:
 a single unit body covered by a housing having an input shaft to which the steering wheel is connected, an output shaft to which the wheel side steering member is connected, a torque sensor which is provided between the input shaft and the output shaft, an electric motor which is driven in correspondence to a detected torque of the torque sensor, and a gear train which transmits a rotation of the electric motor to the output shaft built-in, an elastic member is interposed between an attaching portion provided in the housing and a vehicle body side attaching stay, wherein the elastic member is provided in both sides of the support portion of the vehicle body side attaching stay, and the support portion of the vehicle body side attaching stay is pinched between forked attaching portions provided in the housing via the elastic member. 
 
   
   
     10. A motor-driven steering assist apparatus as claimed in  claim 9 , wherein the housing is constituted by first to third housings,
 the first housing supports an upper end portion of the input shaft and the torque sensor, 
 the second housing supports an upper end portion of the output shaft, the electric motor and the gear train, 
 the third housing supports a lower end portion of the output shaft, and 
 the attaching portion is provided in an outer periphery of the second housing. 
 
   
   
     11. A motor-driven steering assist apparatus as claimed in  claim 10 , wherein the attaching portion comprises attaching bosses provided at a plurality of positions in a circumferential direction of an outer periphery of the second housing. 
   
   
     12. A motor-driven steering assist apparatus as claimed in of  claim 9 , wherein the motor-driven steering assist apparatus is applied to a snowmobile. 
   
   
     13. A motor-driven steering assist apparatus as claimed in of  claim 9 , wherein the motor-driven steering assist apparatus is applied to a snowmobile. 
   
   
     14. A motor-driven steering assist apparatus interposed between a steering wheel and a wheel side steering member, and assisting a steering force which a driver applies to the steering wheel on the basis of a generating torque of an electric motor, comprising:
 a single unit body covered by a housing having an input shaft to which the steering wheel is connected, an output shaft to which the wheel side steering member is connected, a torque sensor which is provided between the input shaft and the output shaft, an electric motor which is driven in correspondence to a detected torque of the torque sensor, and a gear train which transmits a rotation of the electric motor to the output shaft built-in, an elastic member is interposed between an attaching portion provided in the housing and a vehicle body side attaching stay, wherein the housing is constituted by first to third housings, 
 the first housing supports an upper end portion of the input shaft and the torque sensor, 
 the second housing supports an upper end portion of the output shaft, the electric motor and the gear train, 
 the third housing supports a lower end portion of the output shaft, and the attaching portion is provided in an outer periphery of the second housing. 
 
   
   
     15. A motor-driven steering assist apparatus as claimed in  claim 14 , wherein the attaching portion comprises attaching bosses provided at a plurality of positions in a circumferential direction of an outer periphery of the second housing. 
   
   
     16. A motor-driven steering assist apparatus as claimed in of  claim 14 , wherein the motor-driven steering assist apparatus is applied to a snowmobile. 
   
   
     17. A motor-driven steering assist apparatus as claimed in of  claim 14 , wherein the motor-driven steering assist apparatus is applied to a snowmobile.